The present invention relates generally to an apparatus for providing a damping devise for a circuit board coupled in spaced relationship to another circuit board or chassis.
Circuit card assembly spacers are typically used between two circuit boards or between a circuit board and chassis to maintain the minimum spacing requirement and provide support for the circuit boards under vibration loads. The spacer height, weight, and tolerance are major factors in selecting a particular spacer. However, there are cases where a minimal number of spacers are provided because of the above concerns, components installation interference, or simple neglect during the design of the circuit card assembly. All of these issues result in a more flexible circuit board more prone to vibration damage. The spacing members are commonly positioned adjacent to corners of the circuit board and the circuit board itself is commonly rectangular having a pair of long sides. For any of the above reasons, the long sides may be left unsupported between the spacing members permitting vibration in the circuit board substantial enough to cause damage of electronic components which are attached to the circuit board.
U.S. Pat. No. 5,999,414 provides a very elaborate system including a contact, protruding end, curved top section, elastomeric insert, and fasteners to hold a stack of printed circuit boards together. The system provides resistance against excessive shock and vibrations, and electrical power (signals) conduction between the boards. However, this design is relatively complex, permits heat exchange between circuit boards, and inhibits access to the circuit boards without disassembly and separation of the stacked circuit boards.
U.S. Pat. No. 5,841,638 provides a method of stacking a collection of printed circuit boards for a crash-proof flight recorder utilizing a spacer or standoff. The spacer of this prior art reference performs both support and electrical conduction similar to the structure of the device taught in the U.S. Pat. No. 5,999,414 patent. Similarly, this design is also relatively complex, permits heat exchange between circuit boards, and inhibits access to the circuit boards without disassembly and separation of the stacked circuit boards.
U.S. Pat. No. 3,904,934 provides electrical interconnections, thermal control and mechanical integrity in electronic systems where the disclosed electrical systems comprise circuit boards and supports alternately stacked circuit boards between two thick pressure plates. Clamp screws provide clamping pressure for the electronic assembly during fabrication. Leaf springs are used as coupling and flexure compensating elements extending along two complete edges. Again, this design is relatively complex, permits heat exchange between circuit boards, and inhibits access to the circuit boards without disassembly and separation of the stacked circuit boards.
As can be seen, there is a need for damping of vibration of a circuit board coupled in spaced relationship to another circuit board or chassis without electrical or heat conduction between boards. Further, there is a need for a damping assembly that is easily installed or removed to maintain some access to the circuit board without complete disassembly of the circuit card assembly.